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Homework Help: Help verify this question about average acceleration?

  1. Jul 8, 2011 #1
    1. The problem statement, all variables and given/known data

    A car traveling in a straight line has a velocity of 5.51 m/s at some instant. After 7.36 s, its velocity is 8.09 m/s.
    What is its average acceleration in this time interval?
    Answer in units of m/s^2.

    2. Relevant equations

    avg. acceleration = (v2 - v1) / (t2 - t1)

    3. The attempt at a solution

    (8.09 m/s) - (5.51 m/s) / (7.36 s - 0 s)
    = .350 m/s^2

    ---------------

    The only thing I'm not sure about is the "0s" used above: is that the right interval? I'm confused if I'm approaching this right, so could anyone help me please?

    Thanks!
     
  2. jcsd
  3. Jul 8, 2011 #2

    Doc Al

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    Staff: Mentor

    Looks perfect to me. Think of it as a = Δv/Δt, where the Δt is the time interval during which the velocity changes.
     
  4. Jul 8, 2011 #3

    berkeman

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    Staff: Mentor

    Yes, it's fine to call the start time t=0. You could also just call the denominator delta_t=7.36s.
     
  5. Jul 8, 2011 #4
    Ok, thank you guys! It does make more sense to think of it as Δv/Δt, so thank you!
     
  6. Jul 8, 2011 #5

    berkeman

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    Staff: Mentor

    Oh, man. Doc beat me to it again. Sigh.
     
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